Well, I got a fast response from him. Here is what he says:

I have 2sets in stock now for XT660R but no confirm if the same attachment is same (for XT660Z).
But if you know it fit - is still available.
Material stainless steel.
Payment via PayPal.
Shipping worldwide.
Price is �70/set
If you are not satisfied return back (money back).

So, the �70 question is, are XT660R and XT660Z foot peg mounts the same?